+ * If a frame header is located then true is returned. The first two bytes of the header will have + * been written into {@link #headerScratch}, and the position of the source will have been + * advanced to the byte that immediately follows these two bytes. + *
+ * If a frame header is not located then the position of the source will have been advanced to the + * limit, and the method should be called again with the next source to continue the search. + * + * @param source The source from which to read. + * @return True if the frame header was located. False otherwise. + */ + private boolean findHeader(ParsableByteArray source) { + byte[] mpaData = source.data; + int startOffset = source.getPosition(); + int endOffset = source.limit(); + for (int i = startOffset; i < endOffset; i++) { + boolean byteIsFF = (mpaData[i] & 0xFF) == 0xFF; + boolean found = lastByteWasFF && (mpaData[i] & 0xF0) == 0xF0; + lastByteWasFF = byteIsFF; + if (found) { + source.setPosition(i + 1); + // Reset lastByteWasFF for next time. + lastByteWasFF = false; + headerScratch.data[0] = (byte) 0xFF; + headerScratch.data[1] = mpaData[i]; + bytesRead = 2; + return true; + } + } + source.setPosition(endOffset); + return false; + } - private static final int[][] MPA_SAMPLES_PER_FRAME = new int[][] { - { // MPEG 1 - 384, // Layer1 - 1152, // Layer2 - 1152 // Layer3 - }, - { // MPEG 2, 2.5 - 384, // Layer1 - 1152, // Layer2 - 576 // Layer3 - } - }; - - /** - * Coefficients (samples per frame / 8): - * - * @index = LSF - * @index = Layer - */ - - private static final int[][] MPA_COEFFICIENTS = new int[][] { - { // MPEG 1 - 12, // Layer1 - 144, // Layer2 - 144 // Layer3 - }, - { // MPEG 2, 2.5 - 12, // Layer1 - 144, // Layer2 - 72 // Layer3 - } - }; - - /** - * slot size per layer: - * - * @index = Layer - */ - - private static final int[] MPA_SLOT_SIZE = new int[] { - 4, // Layer1 - 1, // Layer2 - 1 // Layer3 - }; - - public MpaReader(TrackOutput output) { - super(output); - mpaScratch = new ParsableBitArray(new byte[HEADER_SIZE + CRC_SIZE]); - state = STATE_FINDING_SYNC; + /** + * Attempts to read the remaining two bytes of the frame header. + *
+ * If a frame header is read in full then true is returned. The media format will have been output + * if this has not previously occurred, the four header bytes will have been output as sample + * data, and the position of the source will have been advanced to the byte that immediately + * follows the header. + *
+ * If a frame header is not read in full then the position of the source will have been advanced
+ * to the limit, and the method should be called again with the next source to continue the read.
+ *
+ * @param source The source from which to read.
+ * @return True if the frame header was read in full. False otherwise.
+ */
+ private boolean readHeaderRemainder(ParsableByteArray source) {
+ int bytesToRead = Math.min(source.bytesLeft(), HEADER_SIZE - bytesRead);
+ source.readBytes(headerScratch.data, bytesRead, bytesToRead);
+ bytesRead += bytesToRead;
+ if (bytesRead < HEADER_SIZE) {
+ return false;
}
- @Override
- public void consume(ParsableByteArray data, long pesTimeUs, boolean startOfPacket) {
- if (startOfPacket) {
- timeUs = pesTimeUs;
- }
- while (data.bytesLeft() > 0) {
- switch (state) {
- case STATE_FINDING_SYNC:
- if (skipToNextSync(data)) {
- bytesRead = 0;
- state = STATE_READING_HEADER;
- }
- break;
- case STATE_READING_HEADER:
- int targetLength = hasCrc ? HEADER_SIZE + CRC_SIZE : HEADER_SIZE;
- if (continueRead(data, mpaScratch.data, targetLength)) {
- parseHeader();
- bytesRead = targetLength;
- state = STATE_READING_SAMPLE;
- }
- break;
- case STATE_READING_SAMPLE:
- int bytesToRead = Math.min(data.bytesLeft(), sampleSize - bytesRead);
- output.sampleData(data, bytesToRead);
- bytesRead += bytesToRead;
- if (bytesRead == sampleSize) {
- output.sampleMetadata(timeUs, C.SAMPLE_FLAG_SYNC, sampleSize, 0, null);
- timeUs += frameDurationUs;
- bytesRead = 0;
- state = STATE_FINDING_SYNC;
- }
- break;
- }
- }
+ if (!hasOutputFormat) {
+ headerScratch.setPosition(0);
+ int headerInt = headerScratch.readInt();
+ MpegAudioHeader synchronizedHeader = new MpegAudioHeader();
+ MpegAudioHeader.populateHeader(headerInt, synchronizedHeader);
+ MediaFormat mediaFormat = MediaFormat.createAudioFormat(
+ Mp3Extractor.MIME_TYPE_BY_LAYER[synchronizedHeader.layerIndex], Mp3Extractor.MAX_FRAME_SIZE_BYTES,
+ C.UNKNOWN_TIME_US, synchronizedHeader.channels, synchronizedHeader.sampleRate,
+ Collections.
+ * If a frame is read in full then true is returned. The frame will have been output, and the
+ * position of the source will have been advanced to the byte that immediately follows the end of
+ * the frame.
+ *
+ * If a frame is not read in full then the position of the source will have been advanced to the
+ * limit, and the method should be called again with the next source to continue the read.
+ *
+ * @param source The source from which to read.
+ * @return True if the frame was read in full. False otherwise.
+ */
+ private boolean readFrame(ParsableByteArray source) {
+ int bytesToRead = Math.min(source.bytesLeft(), sampleSize - bytesRead);
+ output.sampleData(source, bytesToRead);
+ bytesRead += bytesToRead;
+ if (bytesRead < sampleSize) {
+ return false;
}
- /**
- * Continues a read from the provided {@code source} into a given {@code target}. It's assumed
- * that the data should be written into {@code target} starting from an offset of zero.
- *
- * @param source The source from which to read.
- * @param target The target into which data is to be read.
- * @param targetLength The target length of the read.
- * @return Whether the target length was reached.
- */
- private boolean continueRead(ParsableByteArray source, byte[] target, int targetLength) {
- int bytesToRead = Math.min(source.bytesLeft(), targetLength - bytesRead);
- source.readBytes(target, bytesRead, bytesToRead);
- bytesRead += bytesToRead;
- return bytesRead == targetLength;
- }
+ output.sampleMetadata(timeUs, C.SAMPLE_FLAG_SYNC, sampleSize, 0, null);
+ timeUs += frameDurationUs;
+ bytesRead = 0;
+ return true;
+ }
- /**
- * Locates the next sync word, advancing the position to the byte that immediately follows it.
- * If a sync word was not located, the position is advanced to the limit.
- *
- * @param pesBuffer The buffer whose position should be advanced.
- * @return True if a sync word position was found. False otherwise.
- */
- private boolean skipToNextSync(ParsableByteArray pesBuffer) {
- byte[] mpaData = pesBuffer.data;
- int startOffset = pesBuffer.getPosition();
- int endOffset = pesBuffer.limit();
- for (int i = startOffset; i < endOffset - 1; i++) {
- int syncBits = ((mpaData[i] & 0xFF) << 8 ) | (mpaData[i + 1] & 0xFF);
- if ((syncBits & 0xFFF0) == 0xFFF0) {
- hasCrc = (mpaData[i + 1] & 0x1) == 0;
- pesBuffer.setPosition(i);
- return true;
- }
- }
- pesBuffer.setPosition(endOffset);
- return false;
- }
-
- /**
- * Calculates MPEG Audio frame size
- *
- * @param layer The MPEG layer
- * @param LSF Low Sample rate Format (MPEG 2)
- * @param bitrate The bitrate in bits per second
- * @param samplesPerSec The sampling rate in hertz
- * @param -paddingSize
- * @return Frame size in bytes
- */
- private static int CalcMpaFrameSize (int layer, int LSF, int bitrate, int samplesPerSec, int paddingSize) {
- return (int)(Math.floor(MPA_COEFFICIENTS[LSF][layer] * bitrate / samplesPerSec) + paddingSize) * MPA_SLOT_SIZE[layer];
- }
-
- /**
- * Parses the sample header.
- */
- private void parseHeader() {
- int headerLength = hasCrc ? HEADER_SIZE + CRC_SIZE : HEADER_SIZE;
-
- if (!hasOutputFormat) {
- mpaScratch.setPosition(0);
- mpaScratch.skipBits(12);
- int isLSF = (!mpaScratch.readBit()) ? 1 : 0;
- int layer = mpaScratch.readBits(2) ^ 3;
- mpaScratch.skipBits(1);
- int audioObjectType = 32 + layer;
- int bitRate = MPA_BITRATES[isLSF][layer][mpaScratch.readBits(4)];
- int sampleRate = MPA_SAMPLING_RATES[3 - isLSF][mpaScratch.readBits(2)];
- int sampleRateIndex = CodecSpecificDataUtil.getSampleRateIndex(sampleRate);
- int paddingBit = (mpaScratch.readBit()) ? 1 : 0;
- mpaScratch.skipBits(1);
- int channelConfig = mpaScratch.readBits(2) == 3 ? 1 : 2;
-
- byte[] audioSpecificConfig = CodecSpecificDataUtil.buildAudioSpecificConfig(
- audioObjectType, sampleRateIndex, channelConfig);
- Pair